Institute for Nuclear and Particle Astrophysics (INPA) at LBNL
The INPA Seminar weekly talks are on Fridays, starting at 12:00 pm, unless informed otherwise. The seminar talk starts with a brief presentation of the weekly scientific news. Typically, the talks conclude by 1:00 pm. The seminars are held in the Sessler Conference Room, located in Bldg. 50A- 5132.
The committee members are:
The seminar schedule for the Institute for Nuclear and Particle Astrophysics (INPA) is tentative and becomes final a few days before the Friday talk.
Please send all suggestions for future INPA talks and speakers to the INPA Committee.
To be added to the INPA News Mailing List, please contact Erica Hall.
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Lauren Ice (ASU) – Measurement of the Two-Photon Exchange Contribution to Elastic Lepton-Proton Scattering with the OLYMPUS Experiment
February 27, 2017 @ 12:00 pm - 1:00 pm
The OLYMPUS experiment measured the two-photon exchange contribution to elastic electron-proton scattering, which is thought to be the most likely candidate to resolve the discrepancy observed between polarized and unpolarized measurements of the proton electric-to-magnetic form factor ratio. To deterimine the two-photon exchange contribtuion, OLYMPUS measured the positron-proton to electron-proton elastic scattering cross section ratio over a wide range of four-momentum transfer from 0.6 < Q2 < 2.2 (GeV/c)2 and virtual photon polarizaton from 0.456 < < 0.978. The two-photon exchange contribution is correlated to the deviation of the cross section ratio from unity.
In 2012, the OLYMPUS experiment collected over 4 fb−1 of e+p and e−p scatter-ing data using electron and positron beams incident on a hydrogen gas target. The scattered leptons and protons were measured exclusively with a large acceptance spec-
trometer. OLYMPUS observed a slight rise in σe+p/σe−p of at most 1-2% over the Q2 range. This talk will discuss the motivations, experiment, analysis method, and the preliminary results for the cross section ratio as measured by OLYMPUS.
INPA guests from campus can now come to the lab early on Fridays. The INPA Common Room (50-5026) is reserved for our guests from 10:00 a.m. to 12:00 noon and from 1 p.m. to 5 p.m. Note that the seminars are now held in 50A-5132 to accommodate a more significant number of attendees.
CPTea Series (also known as INPA Tea Series)
The Physics Division CPTea Series invites you to an In-Person Tea Series 1st Friday of every month at 3:30 pm INPA Conference Room 50-5026.
Everyone is welcome to attend the open forum. Tea and light refreshments will be served.
INPA Common Room (50-5026)
Fridays
3:30 pm
Access to the Lab
For a shuttle pass, please email Erica Hall. The pass is only valid for the day of the seminar.